X-ray apparatus



Jan. 8, 1929.

' 1,698,334 W. K. KEARSLEY, JR

X-RAY APPARATUS Original Filed Jan. 31. 1922 JJ' I A; II p NWWWW\ WW7 II 1' 2 .9

Inventor: William K. Kearsl'eg J11, 5 I His Attorney.

Patented Jan. 8, 1929.

I UNITED STATES PATENT: "oF I CE.

WILLIAM K. EAnsLEY, an, on SCHENECTADY, new YORK, ASSIGNOR T0 GENERAL ELEo'rRIo COMPANY, AQGRiPOR-ATION on NEW YORK.

X-RAY APPARATUS.

Application filed January 31, 1922, Serial No. 533,070. Renewed October I4, 1927.

The present invention relates tothe reg'uA lation-of X-ray devices and comprises in particular adevice for so controlling an X-ray tube that an X-ray outputfof substantially constant radiographic effect is obtained even though the supply voltage varies materially.

Ina prior Patent No. 1,653,102, issued De;

cember 20, 1927, I have described a-regulat ing device whereby the operating current of an X-ray tube is maintained substantially constant under varying'operating conditions. In an X-ray apparatussupplied With current for heating the cathode derived from the same source as the current for generating X- rays, the operation of my prior regulator maintains the current throughv the X-ray tube substantially constant even though the supply voltage'should increase. However,

the increase of voltage impressed on the ray tube results in the production of X-rays of greater penetrability. .Hence, during ordinary use of the tube, for example, in chagnostic work, the efiect on a phonographic surface may be increased by an increase of.

supply voltage even though the operating current and consequently the quantity of X- rays remains substantially unchanged.

. luy present invention comprises an improved regulator provided with means whereby the current through the tube is automatically varied inversely with any change of applied voltage to obtain a substantially constant radiographic effect.

The accompanying drawing diagrammatically illustrates one embodiment of my invention.

The X-ray tube 1 is supplied With electric current from the high tension secondary of a transformer 2 by the conductors 3, 4. The X- ray tube has been illustrated somewhat conventionally as its construction is well understood, see for example, U. S. patent to Coolidge 1,326,029. shown) is supplied with current by the low tension secondary of a transformer 5, the

' transformer primary receiving current from X-ray tube.

The cathode filament (not two windings 14, 15, th winding being connected across the conductors 6, 7 inseries 1 with an inductance coil 16, and the Winding 15 being connected by the conductors 17, 18 in I series with the coils 19, 20 of the trans Withthe variations of voltage oftlie supply source, and hence also varies directlyvvith the voltage impressed on the electrodes of the X- raytube as the voltage of the secondary of the transformer is proportional to the voltage of the primary. The effect of coil 15lWill vary with'the variations of current through the so proportioned that with a substantially constant given supply voltage the relative penode of make and break of the contacts 10, 11

Willbe of. such relative duration that the curincrease ofvoltage lengthens the period of break reducing the cathodeheating current Preferably these two coils are and conversely a decrease ,ofsupply voltage 3 shortens the period of break, increasing the cathode; heating current. As the low tension heating current determines the electron emis sion of the cathode and the electron emission in turn determines the current through the X- ray tube, an increase or decrease of heating current, as a consequence, will cause an in-' crease or decrease of the high tension current.

Preferably the ampere turns of the tWo windings are so chosen that the current through the X-ray tube will vary inversely in proportion to the square of the line voltage thereby producing nearly a constant effect one photographic film or plate regardless of supply voltage changes.

The effect of the winding 14 is magnified by the reactance 16, which ispreferably operated at a point on the saturation curve Where the current increases rapidly With in.- crease of voltage.

That I claim as new and desire to secure by Letters Patent of the United States, is:

1. An X-ray apparatus for. incandescent cathode X-ray tubes comprising a main operating circuit, a transformer having a primary Winding connected thereto, a cathode heating circuit, make and break contact in said heat ing circuit, and electromagnetic means for operating aid contacts including a Winding responsive to the current in the secondary of said tl ansiornier and a. Windingresponsive to thevoltage of said main circuit.

2. An X-ray apparatus comprising the tor responsive to both the current traversing saidtube and voltage'of said mainsu'pply cir- 1mm tojregulate the heating current n said \"fir'st circuitto -produce a substantially pre- ,determined radiographic efi'ect from said X- My tube in a. given time."

.3. An 'X-ray apparatus coinprising elec% t i ran f ming mea m ga pup winding a a? S p- Willdlllg zt'rically connected to each other, and a vibrat- 5 ing regulator having voltage-varying means f 111 circuit with said stepidown Winding and having an operating coil responsive to current insald step-up wlnd ngand another coil fe-onnected tobe responslve to voltage var1ationsin said transforming means. y 4. 'AnjX-ray apparatus comprlslng a stepelectrically. connected, and, a vibratingbregu- 7 "later llfl-YlIlg a make and break contact n one ofgthe circuits ofsaid step-down transformer,

andhaving one operating coil in series Witha secondary Winding of said step-up trans former and another operatingcoil connected inshunt' to a primary winding of said stepj up transformer. T 5. ,Incombination with athermionic device, means for Lfurnishingnlniain load current i ",t erefQrrme -ns f rffu n in n i l ry said device substantiallyconstant. g V 6'. An apparatus for operating a thermionic frieswith thevoltage-responsiveWinding. V V

In Witness WhereoLIfhave hereunto set my current f r. heating the cathode of said de 40 vice and n cans herebythe current in said auxiliary current may be varied,-said means co nprising a wlnding connected to be responr sie in lts eftect; to varlatlons of the a1nperageolf said loadc-urrent and a Winding re sponsive'in its effect to variations of the voltllagejof said load current, said means being operative to maintain the energy output of Iyray clevlce froln-a variable-energy supply source,'co1nprisin a*n'1ain"l0ad circuit, {an auxiliary cathode regulator*for inaintainingthe current of said auxiliary circuit at such value that an ;X-ray outputofsubstantia-ll constant ra'diographic eating circuit, and a effect will, be produce said regulator having control 1 members respectively responsive to the current Value and voltage "of said load circuit and means cooperating with said regula-tor vhereby the currentin said auxiliary circuit Will be varied inversely with changes of, either characteristic of' said load current.

7; "The combination'of atherniionic X-ray tube a circuitffor supplying. ahigh poten- 7 up transformer, a step-down transformer, {the secondaries of said transforlners being tialload current theref or, a circuit lor furnishing a eathode heating current, a.

-1 egulatorforsaid' heating circuit, said regu- -lator producing a substantially constant ra- "diographic effect in-the X-ray" output of said tube, said regulator having windings respectivelyw responsive to variations of amperage andvoltage of said high potential load Cir? cuit and a reactance Winding connected in sehand this 30th day ofJanu'ary, 1922. JR. 7

CERTIFICATE OF CORRECTION.

Patent No. 1,698,334. Granted January 8, 1929, to

WILLIAM K. KEARSLEY, JR.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction, as follows: Page 1, line 23, for the word "phonogranhic" read "photographic"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 19th day of February, A. D. 1929.

M. J. Moore,

(Seal) Acting Commissioner of Patents. 

